A fuel tank of an automobile includes an excess-feeding regulation valve for preventing fuel from being excessively fed in a fuel tank so that the fuel level in the fuel tank may not rise over a full fuel level, a fuel outflow preventive valve for preventing fuel in the fuel tank from leaking out of the fuel tank when the automobile turns or leans, and the like. While the valves are usually of separate construction, a valve device including both of the valves of a monolithic construction is also known.
For example, JP-H06-297968-A describes an evaporated fuel discharge regulating device for a fuel tank including a case that includes an end plate with first and second openings and a lower space and an upper space formed via the end plate, an evaporation fuel discharge pipe that is connected to an upper portion of the case and communicates with the upper space, a first float valve disposed in the lower space in a vertically movable manner and arranged to close the first opening when a fuel level in the fuel tank reaches near a full fuel level, a second float valve disposed in the lower space in a vertically movable manner and arranged to close the second opening when a fuel level in the fuel tank abnormally rises, and a relief valve disposed above the second opening and arranged to usually close the second opening and to open the second opening when the pressure in the fuel tank reaches a predetermined value or more.
When fuel is fed into the fuel tank and the fuel level reaches near the full fuel level, the first float valve closes the first opening to regulate the fuel so as not to be fed over the full fuel level. Meanwhile, when the fuel sways in the fuel tank, the first and second float valves rise to close the first and second openings to block the fuel flow to the evaporation fuel discharge pipe, which can prevent the fuel from flowing out of the fuel tank.
In the above-described evaporated fuel discharge regulating device, the second float valve for preventing fuel overflow moves toward and away from the second opening which is usually closed by the relief valve biased by a spring.
However, when the fuel greatly sways in the fuel tank, or a large amount of fuel droplets are spread because of vibration during travelling or the like, the fuel sometimes pushes up the relief valve against a biasing force of the spring, which ends up flowing into the upper space through the second opening. As a result, there arises a problem in that fuel in the form of liquid could flow into a discharging outlet communicating with the upper space of the evaporation fuel discharge pipe.